Since I can get a 25% rebate from EWZ if I buy the right model, I have just spent some time at topten.ch which has sections for Gefrierschränke (upright freezers with a door on the side) and Gefriertruhen ("top loader" - chest freezers with a door on the top), but not Tiefkühlschränke.

The words translate as "freezer" or "deep freezer", and they all look like they will go below 0 Celsius, so I am guessing the major difference is the form factor.

Based on the shape, I want a Gefrierschrank.

I spent some time at Siemens' web site looking at their white goods. But the technical data for their nice white boxes don't mention anything that looks like a minimum temperature.

Is it correct to assume that all "Gefrierschränke" go down to the same minimum temperature? Which from memory is about -18 C in the UK.

Can't really answer you question, but we have a Tiefkuhlschrank that goes down to -32C, so maybe a Gefrierschrank only goes down to -18C or half as much. I don't know which consumes less energy, but that is likely the EWZ criterion, i.e., freezer vs. deep freezer.

No, there isn't.

Nothing to add, no temperature or other difference at all same thing two words for it. Only difference is between a Schrank (has a door at the front) and a Truhe (has a door on top).

"Tiefkuhl" and "4* Gefrier" mean the same thing - something that freezes to -18C or below.

Truhe:
Pros: lots of storage, even for large items (ideal for hunters). Often better insulation, as it's easier to insulate the lid as opposed to the door. Loss of cold air less acute (cold air stays at the bottom).
Cons: Access difficult (lifting items out), can lead to a rummaging mess. Need lots of space. Nothing can be stored above it.

Schrank:
Pro: Easy access and easy to range things. Smaller footprint.
Cons: Difficult to store large items. A little less energy efficient than the Truhe.

And EWZ confirmed that stuff has to be on topten.ch before you can buy it and apply for a rebate.

If anyone's interested, I got a copy of the Gefrierschraenke <125cm models and searched for the lowest online prices. There was sometimes a big difference between the list prices and the best deals.

I think it's best described as, a Tiefkühler is the general word for freezer. Tiefkühlschränke are upright freezers where as Tiefkühltruhen are freezer chests.